Deciphering Dysuria

Emerg Med 40(9):29, 2008

By Nicole Watring, MD, and Jon D. Mason, MD

Painful urination can be the result of anything from a simple urinary tract infection to a serious sexually transmitted disease. Here are the clues to look for to determine the etiology.

Millions of people seek medical treatment for dysuria every year. But deciding what painful urination represents can often take some clinical detective work. It can be a symptom of anything from a simple, easily treated infection to something serious and chronic. In this review, we will discuss the most common causes of dysuria, key points to focus on in the history and physical exam, the utility of diagnostic and laboratory testing, and appropriate treatments.

EXTERNAL OR INTERNAL PAIN

Dysuria is categorized as infectious, inflammatory, or obstructive. Determining whether the sensations of dysuria are external or internal helps narrow down the differential diagnosis (see algorithm below). Vaginal infection or inflammation is a common cause of external dysuria in women, whereas balanitis (inflammation of the glans penis) is a common cause in men. Internal dysuria is most often caused by bacterial cystitis or urethritis. Pain at the onset of urination tends to be urethral in origin; suprapubic pain after voiding originates from the bladder.

Urinary frequency is caused by reduced bladder capacity or painful bladder distension. Other causes may include overflow secondary to benign prostatic hypertrophy (BPH), urethral pathology, or a neurologic disorder.

Urinary hesitation, weak stream, intermittency, and dribbling are most commonly caused by urethral obstruction (stricture or BPH), but they may also be due to reduced bladder contractility. Urinary urgency occurs when the bladder trigone or posterior urethra becomes irritated.

A complete medical history is imperative. Comorbidities and potential complications play an important role in patient disposition. For example, patients who have diabetes or who are immunocompromised are more susceptible to opportunistic pathogens. Men who have recently undergone transurethral resection of the prostate (TURP) are at increased risk for complications, including acute prostatitis, cystitis, osteomyelitis, and urosepsis. Patients with a history of vesicoureteral reflux have an increased risk of pyelonephritis.

Obtain a thorough sexual history to assess your patient’s risk factors for sexually transmitted diseases (STDs). Urethral discharge is indicative of urethritis. Vaginal discharge is present in both urethritis and vulvovaginitis. In any sexually active patient with discharge, suspect chlamydia or gonorrhea.

Also ask about timing and other factors associated with the dysuria. Women who experience symptoms only during menstruation may be suffering from endometriosis.

Inspect and palpate the abdomen and flanks for tenderness or masses. Enlarged kidneys suggest a malignancy. An overdistended bladder may be palpated in cases of urinary obstruction and retention. Examine the penis for urethral discharge and meatal lesions that may suggest an infectious condition or anatomic abnormality. Testicular swelling and tenderness is most often caused by a viral infection. Pain along the epididymis suggests a bacterial infection.

A prostate exam is also important. A tender, boggy prostate suggests prostatitis. In general, an enlarged prostate indicates BPH, as opposed to the hard, nodular prostate found with cancer. Perform the prostate exam gently, not only to avoid unnecessary pain, but to avoid inducing bacteremia.

URINARY TRACT INFECTION: MOST COMMON CAUSE

Urinary tract infection (UTI) is the most common cause of dysuria, accounting for 11 million office visits, 1.7 million emergency department visits, and 100,000 hospitalizations annually, with a health care cost of nearly $2.5 billion. Neonates, girls, young women, and older men are most susceptible to UTIs. In women, bacterial cystitis is the most common bacterial infection. Every woman has a 60% lifetime risk of developing bacterial cystitis; one-third of all U.S. women develop the infection before the age of 24. By contrast, men have a lifetime risk of only 13%.

Urinary tract infection is defined as significant bacteriuria with such signs and symptoms as dysuria, hematuria, increased urinary frequency, urgency, hesitancy, suprapubic discomfort (present in only 15% to 20%), and costovertebral angle tenderness. Infections may be acute or chronic.

Urinary tract infection is caused by pathogenic invasion of the urinary tract, which leads to an inflammatory response of the urothelium. Bacteria gain access to the urethral meatus by local contamination or sexual intercourse and ascend into the upper urinary tract. Escherichia coli causes the majority of UTIs (85% of community- and 50% of hospital-acquired UTIs). Staphylococcus saprophyticus causes 10% to 15%; Proteus mirabilis, Staphyloccus aureus, Enterococcus species, and Klebsiella species are responsible for the rest.

Nosocomial infections and those associated with foreign bodies may involve more aggressive organisms such as Pseudomonas aeruginosa, Serratia, Enterobacter, and Citrobacter species. Nonbacterial infections are uncommon but may be found in the immunosuppressed or patients with diabetes, with Candida species being the most common.

Patients at increased risk for UTI include those with obstructions or alterations in flow from tumors, stones and congenital anomalies, and disruption of the mucin layer from instrumentation. For men, bladder outlet obstruction secondary to BPH is another risk factor.

Women are at greater risk for UTI than men, partly because of the relatively short, straight anatomy of the urethra. Ascent of bacteria from the perineum is the most common cause of acute cystitis in women. Pregnancy and alterations in normal vaginal Lactobacillus colonization due to spermicides, antibiotics, and low levels of estrogen are additional risk factors for women. Sexually active women have a higher risk than women who are not sexually active.

DIAGNOSING UTIs

The clinical manifestations of UTI depend on the portion of the urinary tract involved, the etiologic organism, the severity of the infection, and the patient’s ability to mount an immune response. Signs and symptoms include fever, chills, dysuria, urinary urgency or frequency, and cloudy or malodorous urine.

It is important to differentiate simple and complicated UTIs. A woman is considered to have a complicated UTI if she has kidney stones, indwelling foreign bodies, an iatrogenic infection, or an anatomically or functionally abnormal urinary tract, or is immunocompromised or pregnant. Urinary tract infections in men and boys are automatically classified as complicated because the male urethra is longer and therefore more protective against microbial invaders.

Flank pain, along with fever, chills, and possibly nausea and vomiting, may point to acute pyelonephritis. The risk of renal damage is low with uncomplicated UTI and acute pyelonephritis, but chronic pyelonephritis may lead to scarring and impaired renal function. Patients who have frequent or complicated UTIs (or both), whose symptoms last longer than seven days, or who relapse after treatment for a UTI are at risk for pyelonephritis.

Urinalysis is mandatory in all patients with dysuria. The gold standard is evaluation of a spun midstream clean-catch urine specimen. Bacteria or pyuria (or both) are usually found in patients with UTI. Leukocyte esterase is 75% sensitive for detection of UTI (although emergency department studies have demonstrated only 48% sensitivity), but 98% specific. Positive nitrite suggests a UTI (90% specific), but a negative result does not rule it out (sensitivity is only 30%).

A patient who can’t void spontaneously, is too ill or immobilized to void, or is extremely obese will need a catheter. Catheterization also may be performed as part of a urologic evaluation to assess for urinary retention and as a therapeutic measure to relieve obstruction. Bear in mind, though, that 1% to 2% of patients develop a UTI after one catheter insertion, including “minicaths” and pediatric catheters. These instruments should be avoided unless indicated. Tampon insertion can help obtain a clean specimen in women during menses or with profuse vaginal discharge.

A urine culture should be obtained in all complicated UTIs, cases of acute pyelonephritis, patients with epidemiologic risk factors for subclinical pyelonephritis, patients who require hospitalization, children under the age of two, patients who don’t respond to treatment, and those with recurring UTIs. A culture is also indicated if the history suggests UTI but urinalysis shows no evidence of bacteriuria or pyuria. 

Blood cultures, commonly recommended for acute pyelonephritis, are only 30% positive and rarely will change management. A urine culture is considered positive if it grows at least 10,000 colony-forming units (CFU) per milliliter. Some recent studies have shown, however, that a colony count of at least 100 CFU/ml may represent significant bacteriuria and merit treatment in the presence of symptoms; this is likely an early UTI that will progress if left untreated.

Microscopic analysis should also be performed. It’s important to note that only about half of women with dysuria have significant bacteriuria. The presence of any bacteria on a gram stain of noncentrifuged urine is significant and strongly correlates with culture results of more than 10,000 CFU/ml. Pyuria is 96% sensitive for detecting UTI; sterile pyuria suggests prostatitis, Chlamydia infection, nephrolithiasis, urologic neoplasm, or fungal or mycobacterial infection. White blood cell casts indicate pyelonephritis. A red blood cell count of 3 to 5 or more per high-power field indicates hematuria.

When the diagnosis is in doubt, the patient has a history of vaginal or urethral discharge or STD exposure, or the urinalysis is normal, a pelvic exam should be conducted. It is less of a priority when the patient has internal dysuria and urinary frequency but not vaginal discharge or irritation.

Vaginal and cervical cultures or polymerase chain reaction tests may be done to identify gonorrhea and chlamydia. In cases of sexual assault or child abuse, however, cultures must always be obtained because they are considered the gold standard for determining infection and carry more weight in courtroom testimony.

Imaging is not necessary in cases of uncomplicated UTI but is indicated when the diagnosis is in doubt, the patient is severely ill or immunocompromised and not responding to antibiotics, or you suspect complications.

TREATMENT OPTIONS

Trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line treatment for UTI except in geographic areas where TMP-SMX resistance exceeds 20%, in which case fluoroquinolones are first line (see table below). Fluoroquinolones are also considered first-line treatment in complicated UTIs, particularly in men, since these drugs penetrate the prostate. However, using fluoroquinolones rather than TMP-SMX in uncomplicated UTIs when they are not indicated is believed to be a significant factor in raising health care costs and increasing antibiotic resistance.

Resistance to amoxicillin and sulfamethoxazole can be as high as 30%. There is a 15% to 20% resistance rate to nitrofurantoin, and it does not cover S. saprophyticus. Also, no studies have been done with three-day courses of nitrofurantoin. Oral trimethoprim 100 mg twice daily is an alternative. Simple hygiene habits, including voiding before and after sexual intercourse and wiping from front to back, are often advocated to reduce the risk of UTI; however, a recent review found no advantage to these techniques. Drinking cranberry juice has also traditionally been advocated to prevent UTI but has also been shown likely to have no benefit. However, since these methods certainly do not cause any harm, and there is a slight chance they may help, it is still considered standard of care to encourage them.

CAUSES OF URETHRITIS

Urethritis is nearly always caused by infection. Untreated STDs can ascend and cause epididymitis, prostatitis, and orchitis. In men under 35, urethritis is usually sexually transmitted. In men over 35 it’s usually secondary to urinary stasis; coliform organisms are the predominant cause. Chemicals such as those in vaginal sprays, douches, and bubble baths can also cause inflammatory urethritis in women.

Infectious urethritis can be broken up into two categories: gonococcal urethritis (GU) and nongonococcal urethritis (NGU). The prevalence of gonorrhea is 2% to 10%. In heterosexual men, urethritis is usually due to Chlamydia trachomatis, the most widespread reportable STD in the United States. Two-thirds of epididymitis cases in men younger than 35 years old are from Neisseria gonorrhoeae or C. trachomatis.

An estimated 13% to 26% of teenage women have Chlamydia. Besides Chlamydia, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, and Trichomonas vaginalis can also cause NGU. Other less common infectious causes include lymphogranuloma venereum, herpes genitalis, syphilis, and mycobacteria.

DIAGNOSING AND TREATING URETHRITIS

Diagnosis of urethritis is based on one or more of the following: purulent or mucopurulent urethral discharge, a smear of urethral discharge showing at least 5 WBCs per oil immersion field on microscopy, or a first-voided urine that shows leukocyte esterase on a dipstick test or at least 10 WBCs per high-powered field on microscopy. There will be few to no WBCs in a midstream urine specimen in urethritis. It should be noted that women may not have discharge.

All patients should be tested for N. gonorrhoeae and C. trachomatis with either culture or polymerase chain reaction PCR testing. A gram stain of urethral discharge is not necessary. Historically, the stain was used to guide treatment based on the presence or absence of intracellular gram-negative diplococci (gonococcal versus NGU), but current recommendations indicate empiric treatment for both infections. Urinalysis is not necessary if discharge is present. However, it should be performed to exclude cystitis or pyelonephritis in cases of dysuria without discharge.

Treat all patients who have a positive gram stain or culture as well as those with a history consistent with urethritis who might be unreliable for follow-up. Single-dose empiric treatment for uncomplicated urethritis caused by Chlamydia is with azithromycin. An alternative treatment is doxycycline for seven days. Single-dose empiric treatment for uncomplicated urethritis caused by gonorrhea is with cefixime, ceftriaxone, ceftizoxime, cefoxitin administered with probenecid, or cefotaxime.

Always remember to treat for Chlamydia as well. Azithromycin and doxycycline are equally efficacious. Failure to respond suggests reinfection or re-exposure or infection with T. vaginalis or doxycycline-resistant U. urealyticum. A single dose of metronidazole plus a seven-day course of erythromycin is recommended for persistent or recurrent urethritis (see table above).

back to top

Suggested Reading Bremnor JD and Sadovsky R: Evaluation of dysuria in adults. Am Fam Physician 65(8):1589, 2002. Centers for Disease Control and Prevention: Update to CDC’s sexually transmitted diseases treatment guidelines, 2006: fluoroquinolones no longer recommended for treatment of gonococcal infections. MMWR Morb Mortal Wkly Rep 56(14):332, 2007. Claudius H: Dysuria in adolescents. West J Med 172(3):201, 2000. Johns Hopkins University. ABX Guide. Johns Hopkins University on behalf of its Division of Infectious Diseases. Available at: hopkins-abxguide.org. Accessed April 11, 2007. Kurowski K: The women with dysuria. Am Fam Physician 57(9):2155,1998. Litwin MS and Saigal CS, eds: Urologic Diseases in America. US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. US Government Printing Office, 2007; NIH Publication No. 07-5512. Moses S: Nephrolithiasis. Family Practice Notebook. Available at: www.fpnotebook.com/Urology/Renal/Nphrlths.htm. Accessed April 11, 2007. Porpiglia F, et al.: Nifedipine versus tamsulosin for the management of lower ureteral stones. J Urol 172(2):568, 2004. Roberts RG and Hartlaub PP: Evaluation of dysuria in men. Am Fam Physician 60(3):865, 1999. Terris MK and Sajadi KP: Urethritis. WebMD. Available at: www.emedicine.com/med/topic2342.htm. Accessed April 11, 2007. Tintinalli J, et al.: Emergency Medicine: A Comprehensive Study Guide, 6th ed, McGraw-Hill Companies, 2004.

Printable version of this article

E-mail this article